Be sure to list the location of the shoot. If you have a concept ready or storyboarded. If you would like to hire actors. If you would like animation, and effects, etc. The time table for the final video and a link to the music track so the filmmaker can listen and get a sense of how your ideas will sync with the track. Music videos are pretty big productions and take a lot of planning and preparation, contacting crew, stylists, renting gear, etc. Be prepared to compensate the creative and crew for their work.